This invention relates generally to vehicles having heavy-duty tailgates such as those employed on trucks, towed trailers, and containers used for transporting and discharging bulk materials such as rock, sand, mulch, bark, and the like. The invention, more specifically, relates to apparatus for remotely operating a heavy-duty tailgate on a dump truck as either a tailgate rotatable about a vertical axis at one side of the tailgate or as a power-assisted conventional tailgate pivotal about a horizontal axis along the top of the tailgate.
In light duty hauling applications, such as carried out on automobiles of the station wagon style, it has been known to mount a tailgate in such a way that it can be employed as either a manually positioned door or as a manually positioned drop gate. U.S. Pat. No. 3,387,406 to Coker et al; U.S. Pat. No. 3,592,504 to Sandor; and U.S. Pat. No. 4,076,301 to Gergoe exemplify patents which teach manually operated tailgates for automobile station wagons and which are mounted in such a way that the tailgate can manually swing about either a vertical or horizontal axis.
Dump trucks, having conventional tailgates pivoted about a horizontal axis at the top and latched at the bottom, are frequently used for transporting and discharging large debris such as tree stumps, large and heavy rocks, dirt, and sand. However, tailgate apparatus of this kind requires the vehicle operator to leave the cab of the truck and manually unlatch the tailgate each time the dump truck body is to be emptied and manually re-latch the tailgate once the load is discharged.
U.S. Pat. No. 4,691,956 to Hodge; U.S. Pat. No. 3,027,188 to Eichstadt; and U.S. Pat. No. 2,260,504 to Barrett provide dump trucks with tailgates which can be top or bottom hung so that the tailgates may be swung pivotally from the top or bottom as the conditions may require.
U.S. Pat. No. 2,953,408 to Koenig provides a dump truck that permits dumping of the contents of the truck body to either side or to the rear of the dump truck.
More recently, dump trucks are now being equipped with tailgates which are pivoted about a horizontal axis at the top and which also can be opened by rotating about a vertical axis at one side sometimes referred to as the xe2x80x9cbarn doorxe2x80x9d type. However, the operator still must leave the cab of the truck and manually unlatch the tailgate each time the dump truck body is to be emptied and manually relatch the tailgate once the dump truck body has been emptied.
With the above background in mind, the present invention has as its primary object that of providing an improved apparatus for operating a tailgate on a dump truck, or the like, which enables the operator with powered assistance to remotely unlatch and position the tailgate for pivoting on a horizontal axis or to allow rotation on a vertical axis. Other objects will become apparent as the description proceeds.
A dump truck or the like, according to the present invention, utilizes a heavy-duty tailgate which can be opened as referred to above like a xe2x80x9cbarn doorxe2x80x9d and can be easily switched back to a conventional tailgate as the need arises. The tailgate can be unlatched, opened, released, closed, and re-latched with time saving efficiency since the operator remains in the cab of his truck and remotely operates the dumping of material from the truck bed. The tailgate is remotely operated by activation of a power-assist mechanism to control rotation about a vertical axis at one end of the tailgate or pivot about a horizontal axis at the top of the tailgate. Provision is also made for power-assisted remote latching of the invention apparatus during transit and power-assisted remote unlatching of the invention apparatus at the site at which the dump truck contents are discharged.